+
+ <sect2>
+ <title>Explain</title>
+ <para>
+ Zebra maintains a "classic"
+ <ulink url="&url.z39.50.explain;">Explain</ulink> database
+ on the-side.
+ This database is called <literal>IR-Explain-1</literal> and can be
+ searched using attribute Exp-1.
+ </para>
+ <para>
+ The records in the explain database is of type
+ <literal>grs.sgml</literal> and can be retrieved as
+ SUTRS, XML, GRS-1 + ASN.1 Explain.
+ </para>
+ <para>
+ Classic Explain only defines retrieaval of Explain information
+ via ASN.1. Pratically no Z39.50 clients supports this. Fortunately
+ they don't have to - since Zebra allows retrieaval of this information
+ in the other formats.
+ </para>
+ <para>
+ The root element for the Explain grs.sgml records is
+ <literal>explain</literal>, thus
+ <filename>explain.abs</filename> is used for indexing.
+ </para>
+ <note>
+ <para>
+ Zebra <emphasis>must</emphasis> be able to locate
+ <filename>explain.abs</filename> in order to index the Explain
+ records properly. Zebra will work without it but the information
+ will not be searchable.
+ </para>
+ </note>
+ <para>
+ The following Explain categories are supported: CategoryList, TargetInfo,
+ DatabaseInfo, AttributeDetails .
+ </para>
+ <para>
+ The following Explain search atributes are supported:
+ ExplainCategory (1), DatabaseName (3), DateAdded (9), DateChanged(10).
+ See <filename>tab/explain.att</filename> for more information.
+ </para>
+
+ <sect3>
+ <title>Example searches</title>
+
+ <para>
+ List supported categories:
+ <screen>
+ @attr exp1 1=1 categorylist
+ </screen>
+ </para>
+
+ <para>
+ Get targetinfo
+ <screen>
+ @attr exp1 1=1 targetinfo
+ </screen>
+ </para>
+
+ <para>
+ Get databaseinfo record for database <literal>Default</literal>.
+ <screen>
+ @and @attr exp1 1=1 databaseinfo @attr exp1 1=3 Default
+ </screen>
+ </para>
+
+ </sect3>
+ </sect2>